In order to produce oil or gas, a wellbore is typically drilled into a reservoir or adjacent to a reservoir, and one or more tubing strings are positioned within the wellbore. In certain instances, it may be necessary to cut through or sever a tubing string, such as when the tubing string becomes stuck within the wellbore. A jet cutter may be used to sever the tubing string to allow the removal of a portion of the tubing string. Typical jet cutters include explosive loads that are detonated to sever the tubing string. Certain jet cutters, however, do not release sufficient energy upon detonation, leading to an incomplete severance of the tubing string or swelling or flaring at the severance point that can make removal of the tubing string difficult.